The present invention is related to a composite flexible and kink-resistant tube that can be used for medical applications. In particular, the composite tube is capable of transmitting a torque, and of opposing tension and compression forces.
Modern medical procedures make extensive use of a variety of hollow tubes that are inserted in a patient""s body, especially in connection with various non surgical procedures. These procedures are performed to visually inspect the inside of various body cavities, and to remove tissue samples, as well as diseased tissues. This is done without having to cut thorough the patient""s skin and muscles to reach the desired location within a body cavity.
Some examples of the tools used for these procedures include endoscopes, full thickness resectioning devices (FTRD) used to remove large tissue samples from inside the intestine, devices to treat gastro-esophageal reflux disease (GERD), and various catheters. In addition, tubes with a much smaller diameter are used to inspect and to deliver compounds and devices to the vascular system.
The tubes used in these applications typically define a working channel bound by the tube, through which medical devices can be easily introduced in the body cavity, and must meet several requirements. The tubes must be flexible, so that they can follow the shape of the intestine, the esophagus, or of other body cavities without damaging the surrounding tissue, and in some cases without excessive discomfort to the patient. In many cases, the tubes must be capable of resisting stretching under tension, collapsing under compression, or both. This is especially important in endoscopes, that generally have to be pushed through the intestine from outside the body. These medical tubes also must be kink resistant, so that they will not easily jam inside the body cavity, and so that their cross sectional area remains constant. This is important so that other medical devices can be inserted through the tubes without binding. For many applications it is also important that the tube transfer a torque applied to one end of the tube to the other end. For example, this ability is useful to rotate a vision device mounted on the far end of an endoscope, by rotating the near end.
Medical tubes have been constructed that attempt to combine these required characteristics using coils or braids as structural elements. However, the current tubes are generally of small diameter, and are not suitable for use in the digestive tract. When made of a larger diameter, the tubes have an excessively thick wall, which increases their bending stiffness and reduces the size of the working channel through which additional tools can be introduced.
In view of the foregoing, there is a need for a composite tube for medical applications that is flexible and has a thin wall, while also resisting kinking, transmitting torque, and resisting deformation while under tension or compression.
The present invention is directed to a composite tube for medical applications that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the apparatus and method particularly pointed out in the written description and claims hereof, as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention is a flexible composite tube for medical applications having a longitudinal axis, that comprises a tubular braid adapted to transfer a torque along the longitudinal axis, the tubular braid being made of intertwined wire elements, a coil disposed longitudinally along the tube, adapted to limit radial movement of the tubular braid, and a tube-like elastic layer, disposed adjacent the tubular braid, forming a composite element with the tubular braid to restrict relative movement of the wire elements.
In another embodiment, the invention is a flexible composite tube for medical applications, that has a tubular braid made of intertwined wire elements adapted to transfer a torque along a longitudinal axis of the tube, an inner coil disposed longitudinally along the tube, radially inside of the tubular braid, adapted to limit radial contraction of the tubular braid, and an outer coil disposed longitudinally along the tube, radially outside of the tubular braid, adapted to limit radial expansion of the tubular braid.
In yet another embodiment, the invention is a flexible composite tube for medical applications having a longitudinal axis, and having an inner tubular braid disposed along the longitudinal axis, an outer tubular braid disposed radially outside of the inner tubular braid, said inner and outer tubular braids being adapted to transfer a torque along a longitudinal axis of the tube, and being made of intertwined wire elements. The tube has a coil disposed longitudinally along the tube, radially inside of the outer tubular braid and radially outside the inner tubular braid, adapted to limit radial contraction of the outer tubular braid and radial expansion of the inner tubular braid.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.